The present invention relates to an objective lens actuator of an optical disk device for optically writing or reading information on a disklike recording medium.
In a known optical disk device, an objective lens is driven in two directions, i.e. in a direction of an optical axis perpendicular to a face of a disklike recording medium such as a compact disk, an optical disk or the like (hereinbelow, referred to as a "focusing direction F") and in a radial direction parallel to the face of the recording medium (hereinbelow, referred to as a "tracking direction T") so as to correct focusing errors resulting from vertical motion of the recording medium due to its warpage or tracking errors due to radial deviations of the disc, etc. such that recording and reproduction are performed.
In recent years, trends towards portable use and personal use of a compact disk player or a data file device employing an optical disk are gaining momentum and thus, an optical pickup for use in these devices is also required to be made more compact and inexpensive.
FIG. 1 shows one example of a known objective lens actuator of an optical pickup. The known objective lens actuator includes an objective lens 1, a lens holder 2 for holding the objective lens 1, a focusing coil 4 wound around the lens holder 2 and tracking coils 5a to 5d fixed to the lens holder 2. Elastic members 6a to 6d extend substantially in parallel with each other so as to support the lens holder 2. One end of each of the elastic members 6a and 6b is attached to the lens holder 2 through a printed circuit board 9b, and one end of each of the elastic members 6c and 6d is attached to the lens holder 2 through a printed circuit board 9a. Meanwhile, the other end of each of the elastic members 6a to 6d is attached to a stationary member 10. Magnetic yokes 3a and 3b are formed integrally with a base 11. A magnetic circuit is formed by the magnetic yokes 3a and 3b and permanent magnets 8a and 8b.
Operation of the known objective lens actuator of the above described arrangement is described hereinbelow. In order to correct focusing errors resulting form vertical motion of the recording medium due to its warpage or tracking errors due to radial deviations of the disc, etc., the objective lens 1 is driven in the focusing direction F and the tracking direction T as follows. In order to drive the objective lens 1 in the focusing direction F, the lens holder 2 carrying the objective lens 1 is translated, through the elastic members 6a to 6d, by an electrokinetic type focusing transducer in which the focusing coil 4 is disposed in a gap of the magnetic circuit formed by the permanent magnets 8a and 8b and the magnetic yokes 3a and 3b.
Likewise, in order to drive the objective lens 1 in the tracking direction T, the lends holder 2 carrying the objective lens 1 is translated, through the elastic members 6a to 6d, by an electrokinetic type tracking transducer in which the tracking coils 5a to 5d are disposed in the gap of the magnetic circuit formed by the permanent magnets 8a and 8b and the magnetic yokes 3a and 3b. In addition, the known objective lens actuator as a whole is driven by a motor (not shown) in an access direction on the recording medium, which is identical with the tracking direction T.
Generally in the known objective lens actuator of the above described arrangement, wires of phosphor bronze or the like are used as the elastic members 6a to 6d and opposite ends of the wires are soldered to the printed circuit boards 9a and 9b and the stationary member 10. In the case of a so-called moving coil (MC) type drive in which a drive means for driving the objective lens 1 in the focusing direction F and the tracking direction T secures the focusing coil 4 and the tracking coils 5a to 5d to the lens holder 2, ends of the focusing coil 4 and the tracking coils 5a to 5d are soldered to the wires 6a to 6d and the wires 6a to 6d are used as lead wires. Therefore, when the wires 6a to 6d are attached to the lens holder 2 and the stationary member 10, the wires 6a to 6d should be positioned so as to extend substantially in parallel with each other. Meanwhile, the problem also arises that since the diameter of the wires 6a to 6d is as small as 100 to 150 microns, it is difficult to handle the wires 6a to 6d during assembly.